A silicon wafer used as a material for manufacturing electronic components such as semiconductors or solar cells is manufactured through the steps of slicing a single crystalline silicon ingot to a thin slice in a wafer form, lapping to improve the flatness while polishing the wafer to a desired thickness, etching to remove a damage layer inside the wafer, polishing to improve surface mirroring and flatness, cleaning to remove contaminants on a wafer surface, and the like.
In the slicing described above, the ingot is sliced into thin wafer forms by using a wire and slurry.
Recently, a large size of the wafer has become necessary, and an ingot slicing apparatus for slicing the ingot in accordance with this trend is used.
The ingot slicing apparatus is an apparatus for slicing the ingot using a wire provided to be reciprocated at a high speed.
The wafer is produced by applying an abrasive and slurry to the upper surface of the wire capable of reciprocating at a high speed and slicing the ingot by using friction force between the abrasive attached to the wire and the ingot.
A conventional ingot slicing apparatus will be described with reference to FIG. 1.
The conventional ingot slicing apparatus may include an ingot supply apparatus 20 for accommodating and supplying an ingot I, a slicing apparatus 10 provided to slice the ingot I supplied by the ingot supply apparatus 20, and a slurry supply unit 30 provided to supply the slurry S to the slicing apparatus 10. Here, the ingot supply apparatus 20 may be an ingot moving apparatus, and the slicing apparatus 10 may be a wire rotating apparatus.
The ingot supply apparatus 20 may include an ingot storage unit 21 provided to accommodate the ingot I or to move to the slicing apparatus 10, a gusset plate 23 provided so as to confine the ingot I, and a work plate 22 provided to hold the gusset plate 23. Here, the ingot storage unit 21 may be an ingot moving table, the gusset plate 23 may be a slice pad plate, and the work plate 22 may be an ingot clamp.
The slicing apparatus 10 may include a roller 11 provided to be rotatable and a wire 12 provided to be wound to the roller 11 to be reciprocated.
The ingot supply apparatus 20 described above is provided to be movable vertically so that the ingot I may be sliced by moving the ingot I to the wire 12.
The slurry supply unit 30 is provided to apply the slurry S to the wire 12 as shown in the figure.
The conventional ingot slicing apparatus has a problem that the slurry S coated with the ingot I is scattered and flows into the slicing surface of the ingot I.
As a result, the slurry S flows into the sliced interior of the ingot I, and a bellows motion in which the ingot I vibrates in the direction perpendicular to the moving direction of the wire 12 occurs, and thus the noise due to the vibration and the quality of the slicing of the wafer is deteriorated.
Further, since the wire 12 reciprocates in forward and backward directions when the ingot I is being sliced, a thickness of opposite side surfaces is thinner than a center thickness with respect to the center of the wafer, and thus a space generated due to the difference in the thickness described above causes vibration and deflection of the wire 12, and the quality of the wafer is deteriorated.
Furthermore, when the ingot I is being sliced, the amount of the slurry S applied to the surface of the wire 12 is more than necessary, and thus the thickness of the target wafer is thinned.